VISIBLE DEMONSTRATION of the ACTION of AUTOMATIC EXTRACTORS L. E. WARREN Food and Drug Administration, U. S. Dept, of Agriculture, Washington, D. C.
A
VISIBLE demonstration of the action of certain automatic extractors may be shown by the following experiments:
Experiment 1.-Place sufficient chloroform in a Palkin, Murray, and Watkins automatic extractor for solvents heavier than water1 to allow about 50 cc. to flow over into the Erlenmeyer flask. By means of a funnel pow 60 cc. of saturated salt solution into the inner tube. By means of pipets place 10 cc. of water and 0.3 cc. of iodide-iodate solution (0.10 g. of potassium iodide and 0.01 g. of potassium iodate in 10 cc. of water) on the surface of the salt solution. Connect the jacket with a condenser and heat the chloroform in the Erlenmeyer flask. When the solvent begins to drip from the condenser add a few drops of dilute sulfuric a d d through the top of the condenser. Iodine will be liberated from the solution in the inner tube of the extractor and will color the drops of chloroform violet as they fall. The demonstration may be repeated by adding more of the iodide-iodate solution and more diluted sulfuric acid through the condenser. For solvents lighter than water the previous experiment may be varied by using benzene. This experiment is performed as follows:
Experiment 2.-Place 50 cc. of water in a Palkin, Murray, and Watkins automatic extractor for solvents lighter than water and add about 0.3 cc. of iodideiodate solution. Place 75 cc. of benzene in the Erlenmeyer flask and heat the solvent on a hot plate. When the benzene begins to drop from the condenser add a few drops of dilute sulfuric a d d through the top of the condenser. Iodine will be liberated in the aqueous solution and will color the spray of benzene faintly violet as the solvent passes upward. The color in the droplets may not be noticeable but it may be seen, readily in the benzene layer as the solvent collects on the surface of the water. It is believed that these demonstrations will be useful to teachers of analytical and organic chemistry. Cowrl~rrof md. Ens. Chcm.
PALKIN,
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1 PALXIN, MURRAY,AND WATKINS, Itld. Eng. MURRAY, AND W A ~ NAUTOMATIC S E X ~ C T O R (1925).
Chem., 17, 612
